Size-Dependent Tumor Penetration and in Vivo Efficacy of Monodisperse Drug–Silica Nanoconjugates

The size of a nanomedicine strongly correlates with its biodistribution, tissue penetration, and cell uptake. However, there is limited understanding how the size of nanomedicine impacts the overall antitumor efficacy. We designed and synthesized camptothecin–silica nanoconjugates (Cpt–NCs) with monodisperse particle sizes of 50 and 200 nm, two representative sizes commonly used in drug delivery, and evaluated their antitumor efficacy in murine tumor models. Our studies revealed that the 50 nm Cpt–NC showed higher anticancer efficacy than the larger analogue, due presumably to its faster cellular internalization and more efficient tumor accumulation and penetration. Our findings suggest that nanomedicine with smaller sizes holds great promise for improved cancer therapy.